Medium chain acyl coenzyme A dehydrogenase (MCAD) deficiency: the case for screening all newborns

Medium chain acyl coenzyme A dehydrogenase (MCAD) deficiency is the most common inborn error of fatty acid oxidation with a frequency of 1 in 12,000, an estimated four new cases in the state of Oklahoma each year. The first clinical manifestation is a hypoglycemic episode any time between the newborn period to adulthood. Largely due to failure of diagnosis, the first episode can be lethal, with a frequency of early mortality of 25%. We report a child with MCAD deficiency admitted to the OU Medical Center-Children's Hospital to illustrate the molecular basis, clinical features, and management of the disorder and to present the pros and cons of instituting newborn screening in our state. Such screening is already part of routine newborn metabolic screening in four states. In Oklahoma and elsewhere, there is current discussion, which we summarize, on whether or not to include MCAD deficiency in the routine neonatal screening program. We suggest the evidence says, "Start now."